#include <cctk.h>
#include <cctk_Parameters.h>

#include <algorithm>
#include <cassert>
#include <cmath>
#include <cstdlib>

#include "operator_prototypes_3d.hh"
#include "typeprops.hh"

using namespace std;



//
// Grid point locations and their indices:
//
// global   0   4      12      20      28   |
// local    |   0       1       2       3   |
//          |   C       C       C       C   |
//          | f   f   f   f   f   f   f   f |
// local    | 0   1   2   3   4   5   6   7 |
// global   0 2   6  10  14  18  22  26  30 |
//
// Interpolation with even interpolation order:
//    offset zero (fine index = 2 * coarse index):
//       [1]
//    offset one (fine index = 2 * coarse index + 1):
//       [1]
// Interpolation with odd interpolation order:
//    offset zero:
//       [1 1 0]/2
//    offset one:
//       [0 1 1]/2
// The centres of these stencils are located at the coarse grid point
// corresponding to the fine grid point (the interpolation target)
// minus the offset. Example: fine grid 8 -> coarse grid 8, fine grid
// 12 -> also coarse grid 8.



namespace CarpetLib {
  
  
  
#define SRCIND3(i,j,k)                          \
  index3 (i, j, k,                              \
          srcipadext, srcjpadext, srckpadext,   \
          srciext, srcjext, srckext)
#define DSTIND3(i,j,k)                          \
  index3 (i, j, k,                              \
          dstipadext, dstjpadext, dstkpadext,   \
          dstiext, dstjext, dstkext)
#define SRCOFF3(i,j,k)                          \
  offset3 (i, j, k,                             \
           srciext, srcjext, srckext)
#define DSTOFF3(i,j,k)                          \
  offset3 (i, j, k,                             \
           dstiext, dstjext, dstkext)
  
  
    
  namespace coeffs_3d_cc_rf2 {
    
  // 1D interpolation coefficients
  
  template<typename RT, int ORDER>
  struct coeffs1dc {
    static const RT coeffs[];
  };
  
  template<typename RT, int ORDER, int di>
  struct coeffs1d {
    typedef coeffs1dc<RT,ORDER> coeffs_t;
    
    static ptrdiff_t const ncoeffs = ORDER+1;
    static ptrdiff_t const imin    = - ncoeffs/2 + (ORDER % 2 != 0 ? di : 0);
    static ptrdiff_t const imax    = imin + ncoeffs;
    
    static inline
    RT
    get (ptrdiff_t const i)
    {
      static_assert (ncoeffs == sizeof coeffs_t::coeffs / sizeof *coeffs_t::coeffs,
                     "coefficient array has wrong size");
      static_assert (di==0 or di==1, "di must be 0 or 1");
#ifdef CARPET_DEBUG
      assert (i>=imin and i<imax);
#endif
      ptrdiff_t const j = di==0 ? i-imin : ncoeffs-1 - (i-imin);
#ifdef CARPET_DEBUG
      assert (j>=0 and j<ncoeffs);
#endif
      return coeffs_t::coeffs[j];
    }
    
    // Test coefficients
    static
    void
    test ()
    {
      static bool tested = false;
      if (tested) return;
      tested = true;
      
      static_assert
        (ncoeffs == sizeof coeffs_t::coeffs / sizeof *coeffs_t::coeffs,
         "coefficient array has wrong size");
      
      // Test all orders
      bool error = false;
      for (int n=0; n<=ORDER; ++n) {
        RT res = RT(0.0);
        for (ptrdiff_t i=imin; i<imax; ++i) {
          RT const x = RT(i) + RT(0.5);
          RT const y = ipow (x, n);
          res += get(i) * y;
        }
        RT const x0 = RT(0.25) + di * RT(0.5);
        RT const y0 = ipow (x0, n);
        // Allow losing 3 digits:
        CCTK_REAL const eps = RT(1.0e+3) * numeric_limits<RT>::epsilon();
        if (not (fabs (res - y0) < eps)) {
          RT rt;
          ostringstream buf;
          buf << "Error in prolongate_3d_cc_rf2::coeffs_3d_cc_rf2\n"
              << "   RT=" << typestring(rt) << "\n"
              << "   ORDER=" << ORDER << "\n"
              << "   di=" << di << "\n"
              << "   n=" << n << "\n"
              << "   y0=" << y0 << ", res=" << res;
          CCTK_WARN (CCTK_WARN_ALERT, buf.str().c_str());
          error = true;
        }
      } // for n
      if (error) {
        CCTK_WARN (CCTK_WARN_ABORT, "Aborting.");
      }
    }
  };
  
  
  
#define TYPECASE(N,RT)                          \
                                                \
  template<>                                    \
  const RT coeffs1dc<RT,0>::coeffs[] = {        \
    +1 / RT(1.0)                                \
  };                                            \
                                                \
  template<>                                    \
  const RT coeffs1dc<RT,1>::coeffs[] = {        \
    +1 / RT(4.0),                               \
    +3 / RT(4.0)                                \
  };                                            \
                                                \
  template<>                                    \
  const RT coeffs1dc<RT,2>::coeffs[] = {        \
    + 5 / RT(32.0),                             \
    +30 / RT(32.0),                             \
    - 3 / RT(32.0)                              \
  };                                            \
                                                \
  template<>                                    \
  const RT coeffs1dc<RT,3>::coeffs[] = {        \
    -  5 / RT(128.0),                           \
    + 35 / RT(128.0),                           \
    +105 / RT(128.0),                           \
    -  7 / RT(128.0)                            \
  };                                            \
                                                \
  template<>                                    \
  const RT coeffs1dc<RT,4>::coeffs[] = {        \
    -  45 / RT(2048.0),                         \
    + 420 / RT(2048.0),                         \
    +1890 / RT(2048.0),                         \
    - 252 / RT(2048.0),                         \
    +  35 / RT(2048.0)                          \
  };                                            \
                                                \
  template<>                                    \
  const RT coeffs1dc<RT,5>::coeffs[] = {        \
    +  63 / RT(8192.0),                         \
    - 495 / RT(8192.0),                         \
    +2310 / RT(8192.0),                         \
    +6930 / RT(8192.0),                         \
    - 693 / RT(8192.0),                         \
    +  77 / RT(8192.0)                          \
  };
  
#define CARPET_NO_COMPLEX
#define CARPET_NO_INT
#include "typecase.hh"
#undef TYPECASE
  
  } // namespace coeffs_3d_cc_rf2
  
  using namespace coeffs_3d_cc_rf2;
  
  
  
  // 0D "interpolation"
  template <typename T, int ORDER>
  static inline
  T
  interp0 (T const * restrict const p)
  {
    return * p;
  }
  
  // 1D interpolation
  template <typename T, int ORDER, int di>
  static inline
  T
  interp1 (T const * restrict const p,
           size_t const d1)
  {
    static_assert (di==0 or di==1, "di must be 0 or 1");
    typedef typename typeprops<T>::real RT;
    typedef coeffs1d<RT,ORDER,di> coeffs;
    T res = typeprops<T>::fromreal (0);
    for (ptrdiff_t i=coeffs::imin; i<coeffs::imax; ++i) {
      res += coeffs::get(i) * interp0<T,ORDER> (p + i*d1);
    }
    return res;
  }
  
  // 2D interpolation
  template <typename T, int ORDER, int di, int dj>
  static inline
  T
  interp2 (T const * restrict const p,
           size_t const d1,
           size_t const d2)
  {
    static_assert (dj==0 or dj==1, "dj must be 0 or 1");
    typedef typename typeprops<T>::real RT;
    typedef coeffs1d<RT,ORDER,dj> coeffs;
    T res = typeprops<T>::fromreal (0);
    for (ptrdiff_t i=coeffs::imin; i<coeffs::imax; ++i) {
      res += coeffs::get(i) * interp1<T,ORDER,di> (p + i*d2, d1);
    }
    return res;
  }
  
  // 3D interpolation
  template <typename T, int ORDER, int di, int dj, int dk>
  static inline
  T
  interp3 (T const * restrict const p,
           size_t const d1,
           size_t const d2,
           size_t const d3)
  {
    static_assert (dk==0 or dk==1, "dk must be 0 or 1");
    typedef typename typeprops<T>::real RT;
    typedef coeffs1d<RT,ORDER,dk> coeffs;
    T res = typeprops<T>::fromreal (0);
    for (ptrdiff_t i=coeffs::imin; i<coeffs::imax; ++i) {
      res += coeffs::get(i) * interp2<T,ORDER,di,dj> (p + i*d3, d1, d2);
    }
    return res;
  }
  
  
  
  // Check interpolation index ranges
  template <typename T, int ORDER>
  static inline
  void
  check_indices0 ()
  {
  }
  
  template <typename T, int ORDER, int di>
  static inline
  void
  check_indices1 (ptrdiff_t const is,
                  ptrdiff_t const srciext)
  {
#ifdef CARPET_DEBUG
    typedef typename typeprops<T>::real RT;
    typedef coeffs1d<RT,ORDER,di> coeffs;
    assert (is + coeffs::imin >= 0);
    assert (is + coeffs::imax <= srciext);
    check_indices0<T,ORDER> ();
#endif
  }
  
  template <typename T, int ORDER, int di, int dj>
  static inline
  void
  check_indices2 (ptrdiff_t const is,
                  ptrdiff_t const js,
                  ptrdiff_t const srciext,
                  ptrdiff_t const srcjext)
  {
#ifdef CARPET_DEBUG
    typedef typename typeprops<T>::real RT;
    typedef coeffs1d<RT,ORDER,dj> coeffs;
    assert (js + coeffs::imin >= 0);
    assert (js + coeffs::imax <= srcjext);
    check_indices1<T,ORDER,di> (is, srciext);
#endif
  }
  
  template <typename T, int ORDER, int di, int dj, int dk>
  static inline
  void
  check_indices3 (ptrdiff_t const is,
                  ptrdiff_t const js,
                  ptrdiff_t const ks,
                  ptrdiff_t const srciext,
                  ptrdiff_t const srcjext,
                  ptrdiff_t const srckext)
  {
#ifdef CARPET_DEBUG
    typedef typename typeprops<T>::real RT;
    typedef coeffs1d<RT,ORDER,dk> coeffs;
    assert (ks + coeffs::imin >= 0);
    assert (ks + coeffs::imax <= srckext);
    check_indices2<T,ORDER,di,dj> (is,js, srciext,srcjext);
#endif
  }
  
  
  
  template <typename T, int ORDER>
  void
  prolongate_3d_cc_rf2 (T const * restrict const src,
                        ivect3 const & restrict srcpadext,
                        ivect3 const & restrict srcext,
                        T * restrict const dst,
                        ivect3 const & restrict dstpadext,
                        ivect3 const & restrict dstext,
                        ibbox3 const & restrict srcbbox,
                        ibbox3 const & restrict dstbbox,
                        ibbox3 const & restrict,
                        ibbox3 const & restrict regbbox,
                        void * extraargs)
  {
    assert (not extraargs);
    
    static_assert (ORDER>=0, "ORDER must be non-negative");
    
    typedef typename typeprops<T>::real RT;
    coeffs1d<RT,ORDER,0>::test ();
    coeffs1d<RT,ORDER,1>::test ();
    
    
    
    if (any (srcbbox.stride() <= regbbox.stride() or
             dstbbox.stride() != regbbox.stride()))
    {
      CCTK_WARN (0, "Internal error: strides disagree");
    }
    
    if (any (srcbbox.stride() != reffact2 * dstbbox.stride())) {
      CCTK_WARN (0, "Internal error: source strides are not twice the destination strides");
    }
    
    if (any (dstbbox.stride() % 2 != 0)) {
      CCTK_WARN (0, "Internal error: destination strides are not even");
    }
    
    // This could be handled, but is likely to point to an error
    // elsewhere
    if (regbbox.empty()) {
      CCTK_WARN (0, "Internal error: region extent is empty");
    }
    
    
    
    ivect3 const regext = regbbox.shape() / regbbox.stride();
    assert (all ((regbbox.lower() - srcbbox.lower() + regbbox.stride() / 2) % regbbox.stride() == 0));
    ivect3 const srcoff = (regbbox.lower() - srcbbox.lower() + regbbox.stride() / 2) / regbbox.stride();
    assert (all ((regbbox.lower() - dstbbox.lower()) % regbbox.stride() == 0));
    ivect3 const dstoff = (regbbox.lower() - dstbbox.lower()) / regbbox.stride();
    
    
    
    // Determine the stencil radius (see diagram at the top of this
    // file)
    ivect3 offsetlo, offsethi;
    {
      assert (all ((regbbox.upper() - srcbbox.lower() + regbbox.stride() / 2) % regbbox.stride() == 0));
      ivect3 const srcend = (regbbox.upper() - srcbbox.lower() + regbbox.stride() / 2) / regbbox.stride();
      ivect const needoffsetlo = srcoff % 2;
      ivect const needoffsethi = srcend % 2;
      for (int d=0; d<3; ++d) {
        if (not needoffsetlo[d]) {
          offsetlo[d] = - coeffs1d<RT,ORDER,0>::imin;
        } else {
          offsetlo[d] = - coeffs1d<RT,ORDER,1>::imin;
        }
        if (not needoffsethi[d]) {
          offsethi[d] = coeffs1d<RT,ORDER,0>::imax - 1;
        } else {
          offsethi[d] = coeffs1d<RT,ORDER,1>::imax - 1;
        }
      }
    }
    
    
    
    if (not regbbox.expand(offsetlo, offsethi).is_contained_in(srcbbox) or
        not regbbox                           .is_contained_in(dstbbox))
    {
      cerr << "ORDER=" << ORDER << "\n"
           << "offsetlo=" << offsetlo << "\n"
           << "offsethi=" << offsethi << "\n"
           << "regbbox=" << regbbox << "\n"
           << "dstbbox=" << dstbbox << "\n"
           << "regbbox.expand=" << regbbox.expand(offsetlo, offsethi) << "\n"
           << "srcbbox=" << srcbbox << "\n";
      CCTK_WARN (0, "Internal error: region extent is not contained in array extent");
    }
    
    
    
    size_t const srcipadext = srcpadext[0];
    size_t const srcjpadext = srcpadext[1];
    size_t const srckpadext = srcpadext[2];
    
    size_t const dstipadext = dstpadext[0];
    size_t const dstjpadext = dstpadext[1];
    size_t const dstkpadext = dstpadext[2];
    
    size_t const srciext = srcext[0];
    size_t const srcjext = srcext[1];
    size_t const srckext = srcext[2];
    
    size_t const dstiext = dstext[0];
    size_t const dstjext = dstext[1];
    size_t const dstkext = dstext[2];
    
    size_t const regiext = regext[0];
    size_t const regjext = regext[1];
    size_t const regkext = regext[2];
    
    size_t const srcioff = srcoff[0];
    size_t const srcjoff = srcoff[1];
    size_t const srckoff = srcoff[2];
    
    size_t const dstioff = dstoff[0];
    size_t const dstjoff = dstoff[1];
    size_t const dstkoff = dstoff[2];
    
    
    
    size_t const fi = srcioff % 2;
    size_t const fj = srcjoff % 2;
    size_t const fk = srckoff % 2;
    
    size_t const i0 = srcioff / 2;
    size_t const j0 = srcjoff / 2;
    size_t const k0 = srckoff / 2;
    
    
    // size_t const srcdi = SRCOFF3(1,0,0) - SRCOFF3(0,0,0);
    size_t const srcdi = 1;
    assert (srcdi == SRCOFF3(1,0,0) - SRCOFF3(0,0,0));
    size_t const srcdj = SRCOFF3(0,1,0) - SRCOFF3(0,0,0);
    size_t const srcdk = SRCOFF3(0,0,1) - SRCOFF3(0,0,0);
    
    
    
    // Loop over fine region
    // Label scheme: l 8 fk fj fi
    
    size_t is, js, ks;
    size_t id, jd, kd;
    size_t i, j, k;
    
    // begin k loop
    k = 0;
    ks = k0;
    kd = dstkoff;
    if (fk == 0) goto l80;
    goto l81;
    
    // begin j loop
  l80:
    j = 0;
    js = j0;
    jd = dstjoff;
    if (fj == 0) goto l800;
    goto l801;
    
    // begin i loop
  l800:
    i = 0;
    is = i0;
    id = dstioff;
    if (fi == 0) goto l8000;
    goto l8001;
    
    // kernel
  l8000:
    check_indices3<T,ORDER,0,0,0> (is,js,ks, srciext, srcjext, srckext);
    dst[DSTIND3(id,jd,kd)] =
      interp3<T,ORDER,0,0,0> (& src[SRCIND3(is,js,ks)], srcdi, srcdj, srcdk);
    i = i+1;
    id = id+1;
    if (i < regiext) goto l8001;
    goto l900;
    
    // kernel
  l8001:
    check_indices3<T,ORDER,1,0,0> (is,js,ks, srciext, srcjext, srckext);
    dst[DSTIND3(id,jd,kd)] =
      interp3<T,ORDER,1,0,0> (& src[SRCIND3(is,js,ks)], srcdi, srcdj, srcdk);
    i = i+1;
    id = id+1;
    is = is+1;
    if (i < regiext) goto l8000;
    goto l900;
    
    // end i loop
  l900:
    j = j+1;
    jd = jd+1;
    if (j < regjext) goto l801;
    goto l90;
    
    // begin i loop
  l801:
    i = 0;
    is = i0;
    id = dstioff;
    if (fi == 0) goto l8010;
    goto l8011;
    
    // kernel
  l8010:
    check_indices3<T,ORDER,0,1,0> (is,js,ks, srciext, srcjext, srckext);
    dst[DSTIND3(id,jd,kd)] =
      interp3<T,ORDER,0,1,0> (& src[SRCIND3(is,js,ks)], srcdi, srcdj, srcdk);
    i = i+1;
    id = id+1;
    if (i < regiext) goto l8011;
    goto l901;
    
    // kernel
  l8011:
    check_indices3<T,ORDER,1,1,0> (is,js,ks, srciext, srcjext, srckext);
    dst[DSTIND3(id,jd,kd)] =
      interp3<T,ORDER,1,1,0> (& src[SRCIND3(is,js,ks)], srcdi,srcdj,srcdk);
    i = i+1;
    id = id+1;
    is = is+1;
    if (i < regiext) goto l8010;
    goto l901;
    
    // end i loop
  l901:
    j = j+1;
    jd = jd+1;
    js = js+1;
    if (j < regjext) goto l800;
    goto l90;
    
    // end j loop
  l90:
    k = k+1;
    kd = kd+1;
    if (k < regkext) goto l81;
    goto l9;
    
    // begin j loop
  l81:
    j = 0;
    js = j0;
    jd = dstjoff;
    if (fj == 0) goto l810;
    goto l811;
    
    // begin i loop
  l810:
    i = 0;
    is = i0;
    id = dstioff;
    if (fi == 0) goto l8100;
    goto l8101;
    
    // kernel
  l8100:
    check_indices3<T,ORDER,0,0,1> (is,js,ks, srciext, srcjext, srckext);
    dst[DSTIND3(id,jd,kd)] =
      interp3<T,ORDER,0,0,1> (& src[SRCIND3(is,js,ks)], srcdi, srcdj, srcdk);
    i = i+1;
    id = id+1;
    if (i < regiext) goto l8101;
    goto l910;
    
    // kernel
  l8101:
    check_indices3<T,ORDER,1,0,1> (is,js,ks, srciext, srcjext, srckext);
    dst[DSTIND3(id,jd,kd)] =
      interp3<T,ORDER,1,0,1> (& src[SRCIND3(is,js,ks)], srcdi,srcdj,srcdk);
    i = i+1;
    id = id+1;
    is = is+1;
    if (i < regiext) goto l8100;
    goto l910;
    
    // end i loop
  l910:
    j = j+1;
    jd = jd+1;
    if (j < regjext) goto l811;
    goto l91;
    
    // begin i loop
  l811:
    i = 0;
    is = i0;
    id = dstioff;
    if (fi == 0) goto l8110;
    goto l8111;
    
    // kernel
  l8110:
    check_indices3<T,ORDER,0,1,1> (is,js,ks, srciext, srcjext, srckext);
    dst[DSTIND3(id,jd,kd)] =
      interp3<T,ORDER,0,1,1> (& src[SRCIND3(is,js,ks)], srcdi,srcdj,srcdk);
    i = i+1;
    id = id+1;
    if (i < regiext) goto l8111;
    goto l911;
    
    // kernel
  l8111:
    check_indices3<T,ORDER,1,1,1> (is,js,ks, srciext, srcjext, srckext);
    dst[DSTIND3(id,jd,kd)] =
      interp3<T,ORDER,1,1,1> (& src[SRCIND3(is,js,ks)], srcdi,srcdj,srcdk);
    i = i+1;
    id = id+1;
    is = is+1;
    if (i < regiext) goto l8110;
    goto l911;
    
    // end i loop
  l911:
    j = j+1;
    jd = jd+1;
    js = js+1;
    if (j < regjext) goto l810;
    goto l91;
    
    // end j loop
  l91:
    k = k+1;
    kd = kd+1;
    ks = ks+1;
    if (k < regkext) goto l80;
    goto l9;
    
    // end k loop
  l9:;
    
  }
  
  
  
#define TYPECASE(N,T)                                           \
                                                                \
  template                                                      \
  void                                                          \
  prolongate_3d_cc_rf2<T,0> (T const * restrict const src,      \
                             ivect3 const & restrict srcpadext, \
                             ivect3 const & restrict srcext,    \
                             T * restrict const dst,            \
                             ivect3 const & restrict dstpadext, \
                             ivect3 const & restrict dstext,    \
                             ibbox3 const & restrict srcbbox,   \
                             ibbox3 const & restrict dstbbox,   \
                             ibbox3 const & restrict,           \
                             ibbox3 const & restrict regbbox,   \
                             void * extraargs);                 \
                                                                \
  template                                                      \
  void                                                          \
  prolongate_3d_cc_rf2<T,1> (T const * restrict const src,      \
                             ivect3 const & restrict srcpadext, \
                             ivect3 const & restrict srcext,    \
                             T * restrict const dst,            \
                             ivect3 const & restrict dstpadext, \
                             ivect3 const & restrict dstext,    \
                             ibbox3 const & restrict srcbbox,   \
                             ibbox3 const & restrict dstbbox,   \
                             ibbox3 const & restrict,           \
                             ibbox3 const & restrict regbbox,   \
                             void * extraargs);                 \
                                                                \
  template                                                      \
  void                                                          \
  prolongate_3d_cc_rf2<T,2> (T const * restrict const src,      \
                             ivect3 const & restrict srcpadext, \
                             ivect3 const & restrict srcext,    \
                             T * restrict const dst,            \
                             ivect3 const & restrict dstpadext, \
                             ivect3 const & restrict dstext,    \
                             ibbox3 const & restrict srcbbox,   \
                             ibbox3 const & restrict dstbbox,   \
                             ibbox3 const & restrict,           \
                             ibbox3 const & restrict regbbox,   \
                             void * extraargs);                 \
                                                                \
  template                                                      \
  void                                                          \
  prolongate_3d_cc_rf2<T,3> (T const * restrict const src,      \
                             ivect3 const & restrict srcpadext, \
                             ivect3 const & restrict srcext,    \
                             T * restrict const dst,            \
                             ivect3 const & restrict dstpadext, \
                             ivect3 const & restrict dstext,    \
                             ibbox3 const & restrict srcbbox,   \
                             ibbox3 const & restrict dstbbox,   \
                             ibbox3 const & restrict,           \
                             ibbox3 const & restrict regbbox,   \
                             void * extraargs);                 \
                                                                \
  template                                                      \
  void                                                          \
  prolongate_3d_cc_rf2<T,4> (T const * restrict const src,      \
                             ivect3 const & restrict srcpadext, \
                             ivect3 const & restrict srcext,    \
                             T * restrict const dst,            \
                             ivect3 const & restrict dstpadext, \
                             ivect3 const & restrict dstext,    \
                             ibbox3 const & restrict srcbbox,   \
                             ibbox3 const & restrict dstbbox,   \
                             ibbox3 const & restrict,           \
                             ibbox3 const & restrict regbbox,   \
                             void * extraargs);                 \
                                                                \
  template                                                      \
  void                                                          \
  prolongate_3d_cc_rf2<T,5> (T const * restrict const src,      \
                             ivect3 const & restrict srcpadext, \
                             ivect3 const & restrict srcext,    \
                             T * restrict const dst,            \
                             ivect3 const & restrict dstpadext, \
                             ivect3 const & restrict dstext,    \
                             ibbox3 const & restrict srcbbox,   \
                             ibbox3 const & restrict dstbbox,   \
                             ibbox3 const & restrict,           \
                             ibbox3 const & restrict regbbox,   \
                             void * extraargs);

#define CARPET_NO_INT
#include "typecase.hh"
#undef TYPECASE
  
  
  
} // namespace CarpetLib